The electrical impulse thus enters right bundle branch, and is carried to the right ventricle (first panel). Here, the left bundle branch no longer conducts electricity. First the left ventricle receives the electrical impulse, then the right.ДЇigure 4 вЂ“ Left Bundle Branch Block (LBBB) As a result, the two ventricles no longer receive the electrical impulse simultaneously. Then, from the left ventricle, the electrical impulse finally makes its way to the right ventricle. Therefore, as the electrical impulse leaves the His bundle, it enters left bundle branch only, and is carried to the left ventricle. In RBBB, the right bundle branch no longer conducts electricity. The in this figure, purple arrows indicate the electrical impulse, traveling down the bundle branches and causing the ventricles to beat simultaneously.Д«BB occurs when one of the bundle branches becomes diseased or damaged, and stops conducting electrical impulses that is, a bundle branch becomes вЂњblocked.вЂќ The chief effect of a bundle branch block is to disrupt the normal, coordinated and simultaneous distribution of the electrical signal to the two ventricles. To form this normal QRS complex, the electrical impuse needs to travel to both ventricles at the same time. Since normally both ventricles receive the electrical impulse at the same time, the normal QRS complex is relatively narrow (generally less than 0.1 second in duration.)ДЇigure 3 вЂ“ Normal Bundle Branch Conduction In this image of a normal ECG, the QRS complex represents the electrical impulse as it is being distributed, via the bundle branch system, throughout the ventricles. When the bundle branches are functioning normally, the right and left ventricles contract nearly simultaneously. The right and left bundle branches send the electrical impulse to the right and left ventricle, respectively. From the His bundle, the electrical impulse enters the two вЂњbundle branchesвЂќ (the right and the left). Leaving the AV node, the electrical impulse penetrates into the ventricles via the His bundle. To summarize, the heartвЂ™s electrical impulse originates in the in the sinus node in the upper right atrium, then spreads across both atria, then travels through the AV node. The bundle branches are an important part of the cardiac electrical system, the system that coordinates muscular contraction to assure that the heart works efficiently as a pump.ДЇigure 1 вЂ“ The Normal Electrical System: AVN = AV node, His = His bundle, RBB = right bundle branch, LBB = left bundle branch, RA = right atrium, RV = right ventricle, LA = left atrium, LV = left ventricle What are the bundle branches, and what do they do? In this article, we will review bundle branch block, its significance, and its treatment. Sometimes BBB itself needs to be treated sometimes it indicates significant underlying cardiac disease that needs to be treated and sometimes it has so little significance that no treatment is necessary at all. Fogoros, M.D., Guide, November 26, 2003, that I reprint here:Д«undle branch block (BBB) is a relatively frequent finding on the electrocardiogram (ECG). I found this great article written by Richard N.

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